<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>树状图</title>
</head>
<style>
    .node circle{
        fill:#fff;
        stroke:steelblue;
        stroke-width: 1.5px;
    }
    .node{
        font: 12px sans-serif;
    }
    .link{
        fill:none;
        stroke:#ccc;
        stroke-width: 1.5px;
    }
</style>
<body>
<script src="d3.js" charset="utf-8"></script>
<script src="test.js"></script>
</body>
</html>